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Consider the following information:
D5S818 | |
---|---|
Allele | Peak Height |
9 | 794 |
11 | 1201 |
The same approach can be used to estimate the mixture percentages and interpret data in a two person mixture case with two alleles at a locus. This information can aid in determining the most likely genotypes of the major and minor contributors.
The following scenarios are possible:
Possible Scenarios | ||
---|---|---|
Scenario | Genotype #1 (Major) | Genotype #2 (Minor) |
1 | 9,9 | 9,11 |
2 | 9,11 | 9,11 |
3 | 9,9 | 11,11 |
4 | 9,11 | 11,11 |
5 | 9,11 | 9,9 |
6 | 11,11 | 9,9 |
7 | 11,11 | 9,11 |
- Scenario #1
This scenario is unlikely because a shared 9 allele would leave a very low percent contribution for Genotype #1. - Scenario #2
If it is assumed that the minor donor contributed 25% and the major donor contributed 75% (based on FGA results).
The estimated peak height percentage would be:- Genotype #1 would be 198/300 x 100 = 66%
- Genotype #2 would be 596/901 x 100 = 66%
- Scenario #3
The percent contribution would be:- Genotype #1 (794 / 794 + 1201) x 100 = 40%
- Genotype #2 (1201 / 794 + 1201) x 100 = 60%
- Scenario #4
In this scenario, 11 is a shared allele, and it is assumed that the contribution is equal to that of the 9 allele which is 794 RFUs (Genotype #1). This would leave Genotype #2 contributing 407 RFUs.
The percent contribution would be:- Genotype #1 = (794 + 794/ 794 + 1201) x 100 = 80%
- Genotype #2 = (407 / 794 + 1201) x 100 = 20%
- Scenario #5
This scenario unlikely since a shared 9 allele would leave a very low percent contribution for Genotype #2. - Scenario #6
See scenario #3, as this is the reverse.
The percent contribution would be:- Genotype #1 (1201 / 794 + 1201) x 100 = 60%
- Genotype #2 (794 / 794 + 1201) x 100 = 40%
- Scenario #7
See scenario #4, as this is the reverse.
In this scenario, 11 is a shared allele and it is assumed that the contribution is equal to that of the 9 allele which is 794 RFUs (Genotype #2). This would leave Genotype #1 contributing 407 RFUs.
The percent contribution would be:- Genotype #1 = (407 / 794 + 1201) x 100 = 20%
- Genotype #2 = (794 + 794/ 794 + 1201) x 100 = 80%
Based on these seven scenarios:
- Scenarios 2, 4, and 7 are possible
- Scenarios 3 and 6 are less likely
- Scenarios 1 and 5 are not likely
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